An analytical tool designed to analyze a sample by an electrochemical technique or an optical technique is generally used. FIGS. 20-22 of the present application show a glucose sensor 9 (See Patent Document 1, for example) as an example of analytical tool for analyzing a sample by an electrochemical technique.
The illustrated glucose sensor 9 is mounted, in use, to an analyzer, and includes a flow path 90 for moving a sample by a capillary force. Specifically, the glucose sensor 9 includes a substrate 93 provided with a working electrode 91 and a counter electrode 92, and a cover 95 bonded to the substrate via a spacer 94. The flow path 90 is defined by the substrate 93, the spacer 94 and the cover 95 and communicates with the outside through an introduction port 96 and an exhaust port 97. In the glucose sensor 9 having this structure, the sample introduced through the introduction port 96 moves through the flow path 90 by the capillary force generated in the flow path 90 while exhausting gas from the flow path 90 through the exhaust port 97.
In the glucose sensor 9, the exhaust port 97 is provided by forming a through-hole in the cover 95. Specifically, the exhaust port 97 is formed by press working a flat plate to punch out part of the flat plate. However, with the method to punch the flat plate, a punched-out piece is produced in press working. The punched-out piece may not completely separate from the cover 95 and may keep adhering to the cover 95. In such a case, in bonding the cover 95 to the substrate 93, the punched-out piece exists between the substrate 93 and the cover 95. Therefore, the punched-out piece is exposed in the flow path 90 to hinder the movement of the sample in the flow path 90 and adversely affect on the measurement results. Further, with the method to form the exhaust port 97 by punching, even when the punched-out piece is properly separated from the cover 95, the punched-out piece needs to be disposed of, which reduces the manufacturing efficiency. Moreover, in the glucose sensor 9 with an exhaust port 97 formed by punching, the exhaust port 97 opens upward at the upper surface 98 of the glucose sensor 9 (cover 95). Therefore, the user may introduce sample erroneously from the exhaust port 97 instead of introducing from the introduction port 96. In this case again, accurate measurement results cannot be obtained.                Patent Document 1: JP-B-H08-1-0208        